PX1 battery completely charge fully for about 200 minutes ( shutdown state, charging through computer USB port ), and full of can be used after about 60 hours charging

Seeing from Data, this is a response to the low impedance earphone design amplifier, 32Ω150mW power is quite small, I felt even that drive 250 ΩDT880PRO is also no problem, just dynamic compressed somewhat. 17HZ 100KHZ also improve the transient performance, many friends may not be clear, the amp data and transient contact is the largest of the conversion rate, and the conversion rate and frequency response have great relations, in other words the wider theoretical frequency conversion rate is higher transient and then performance is better.